1. Field of the Invention
The invention relates to a dispenser for pasty products, comprising a container having a cavity for containing the product. The bottom end of the container is closed by a follower piston slidably is placeable along an inner wall of the container by the action of environmental atmospheric pressure, and upper end of the container is provided with a head assembly including a manually operable delivery mechanism with a pump chamber and a delivery piston therein, and a product dispensing unit with a dispensing passage.
2. Description of the Prior Art
Dispensers of this type are generally known as portable supply units for numerous applications, for instance, for dispensing skin lotions and pasty medical products, household chemicals and shoe polishes, and also for the supply of pasty foods, condiments and spice compositions.
The great number of specific applications each with their respective design requirements has resulted in a great variety of dispensers of different design for use with different pasty products. The dispensing and handling mechanisms of many of these dispensers are rather complicated as regards their construction and/or operation. Numerous dispensers of known construction have been found unable to ensure a clean dispensing operation and accurate metering of the product to be dispensed over an extended period of use.
Already described in German Patent Application 36 01 311.0 is a dispenser for pasty products in which the product is fed to the dispensing mechanism by means of a follower piston subjected to the action of atmospheric pressure, the product entering the pump cylinder through a first valve and being dispensed therefrom through a second valve disposed in the pump piston and through a tubular actuating stem of the piston which incorporates the dispensing outlet passage. This construction requires a relatively expensive double-valve arrangement, and the dispensing of the product is accompanied by a continuous movement of the outlet opening together with the tubular actuating stem, so that it may be difficult to accurately deposit the product to be dispensed at a desired location. Further, it is difficult to provide for dispensing a two component extrusion.